Recurrent kidney stones: why they come back and how to prevent them

The NHS describes kidney stones as hard lumps that form in the kidneys, usually caused by a build-up of chemicals found in the urine. Small stones are common and unlikely to cause symptoms, and may be passed in the urine without being noticed, while larger stones can cause severe pain.

Recurrent stones are a common experience. The NHS states plainly that kidney stones can come back, and NICE's guideline on renal and ureteric stones includes a section specifically on preventing recurrence, including dietary and lifestyle advice, potassium citrate and thiazides. The aim of assessment after a stone is therefore not only to treat the current stone but also to reduce the chance of the next.

The NHS lists the factors that make recurrence more likely: eating a high-protein, low-fibre diet, being inactive or bed-bound, often having kidney or urine infections, having a close family member who also gets kidney stones, and having had kidney stones before. It also lists the general risks for stones: not drinking enough water to stay hydrated, a medical condition that increases the amount of certain chemicals in the body, such as metabolic syndrome, and certain medicines including aspirin, antacids, diuretics and antibiotics.

NICE adds that stone analysis and blood tests can reveal conditions that cause stones to recur, such as cystinuria, uric acid stones and primary hyperparathyroidism. The committee also noted that urine testing can identify metabolic abnormalities such as hypercalciuria and hypocitraturia that can be treated, which can reduce future stones.

The NHS says kidney stone pain usually starts in the side of the tummy or lower back, may spread to the groin, testicles or the area around the opening of the vagina, and may come and go, with periods when it is very severe and periods when it is less painful. Other symptoms include a high temperature or feeling hot, cold or shivery, feeling or being sick, needing to pee often and cloudy pee.

It advises urgent medical help if you have kidney stones that are causing symptoms, and asking for an urgent GP appointment or getting help from NHS 111 if you think you have kidney stones and you are in severe pain, or have a high temperature or feel hot, cold or shivery, because infection with a blocked kidney needs urgent drainage.

• Severe pain in the side or lower back that comes in waves.

• Pain spreading to the groin or genitals.

• Fever, shivering or feeling very unwell.

• Nausea, vomiting or needing to pee often.

• Cloudy or bloody urine.

NICE guideline NG118 recommends discussing diet and fluid intake and advises adults to drink 2.5 to 3 litres of water per day, and children and young people 1 to 2 litres depending on age; adding fresh lemon juice to drinking water; avoiding carbonated drinks; a daily salt intake of no more than 6 g for adults; and not restricting calcium but maintaining a normal intake of 700 to 1,200 mg per day for adults. It also advises following the NICE recommendations on maintaining a healthy lifestyle.

The NHS gives similar advice: drink lots of water, add fresh lemon juice, avoid lots of fizzy, caffeinated or alcoholic drinks, make sure you are getting enough calcium, check the colour of your pee, and do not have too much salt. It advises not making changes to your diet without speaking to your doctor.

For some people medicines are also considered. NICE advises considering potassium citrate for adults with a recurrence of stones that are predominantly calcium oxalate, and considering thiazides for adults with recurrent calcium oxalate stones and hypercalciuria after restricting sodium intake to no more than 6 g a day. In January 2019 the use of thiazides was off-label.

NICE advises considering stone analysis for adults with ureteric or renal stones and measuring serum calcium, and considering referring children and young people to a paediatric nephrologist or paediatric urologist for assessment and metabolic investigations. It notes that stone analysis and blood tests allow the diagnosis of treatable conditions, and that 24-hour urine testing can detect metabolic abnormalities but the committee found no evidence to make a practice recommendation for it.

The NHS says you may be asked to try to collect the stone after you pass it in your pee so that it can be examined, and you will be told how to do this. A doctor will ask about conditions, medicines, diet and family history of stones.

The NHS says most kidney stones can be treated at home with medicine, although they can still be painful and may take a few weeks to pass. You will be advised to drink lots of water and may be offered painkillers, anti-sickness medicines and medicines to help the stones come out. NICE advises an NSAID by any route as first-line treatment for suspected renal colic, with intravenous paracetamol or opioids if needed, and not antispasmodics.

Larger stones may need a procedure in hospital. The NHS describes shock waves applied from outside the body to break up the stone, which does not need anaesthetic, or passing a thin tube up the urethra or through a small cut in the back under general anaesthetic. NICE advises considering watchful waiting for asymptomatic renal stones under 5 mm, and offers shockwave lithotripsy for renal stones under 10 mm in adults, with other approaches such as ureteroscopy for particular situations.

On the NHS, a first stone is usually managed by a GP or the emergency department, with urology for larger stones, procedures and recurrent disease. NICE's metabolic testing recommendations are aimed at identifying those who need further assessment.

Private urology offers quicker imaging and procedures. Whichever route is used, stone analysis, a serum calcium check and a clear fluid and diet plan are the core of recurrence prevention.